In recent years, white pearl color coating compositions containing what is called a luster pigment, the color of which varies with viewing angle, have been appreciated as coating compositions for use on automobile bodies. Such compositions can produce three-dimensional visual effects.
Luster pigments used in the design of such a coating color include interference mica pigments and the like. The interference mica pigments include mica or alumina flakes, coated with a metal oxide, in which the coating can cause light interference, so that pearl-like colors can be produced by the luster of the flake pigment and the interference-induced change in color. Unfortunately, the light interference also tends to produce undesired colors. For example, a white interference mica pigment in a highlight of a coating film looks bluish white (when the coating film is viewed from the front), and a shade of the coating film looks yellowish white (when the coating film is viewed from an oblique direction).
In the automobile industry, it has been desired that a white coating color, in particular, a white pearl coating color should be such that the color of a highlight looks whiter with no bluish interference color and the color of a shade looks white in every direction with no complementary yellow color.
JP 2001-327916 A (Patent Document 1) discloses a method for forming a multi layered pearl coating film including: a colored base coating film with an L value of 20 to 60 for lightness; and a mica-based coating film formed using a luster coating composition (containing mica as a luster pigment) containing titanium dioxide-coated silica flakes at a pigment weight concentration (PWC) within the range of 1 to 10%. According to this invention, the interference mica pigment-containing coating film contains a specific amount of titanium dioxide-coated silica flakes, so that the coating film can be less yellowish when viewed in a shade position.
However, the interference mica pigment used in the invention described in Patent Document 1 causes blue interference to remain when viewed in a highlight, and is less effective in suppressing bluish interference.